The present invention relates to a radio paging receiver for use in radio paging.
Owing to the remarkable progress of circuit integration technology in recent years, more compact radio paging receivers of a greater multiplicity of functions and of smaller power consumption have come to be developed. One aspect of this increase in functional multiplicity is the recent addition of message signals to the previous service of sending the selective calling or paging signal (a specific number assigned to each subscriber) alone. Furthermore, to cope with the expansion of the demand spectrum and to increase the reliability of communication, these paging and message signals are now digitized.
Meanwhile, the display of a message signal is achieved, after the receipt of said paging signal, upon actuation of the function to indicate the receipt of the message signal. There are provided within a receiver a plurality of message signal memory circuits, because the subscriber may be paged very frequently or may not promptly respond to every message signal received. The message signals stored in these memory circuits can be read out by a variety of methods. For instance, where there are n memory circuits, n read-out switches may be provided to enable the subscriber to operate in one action the switch corresponding to the particular memory circuit in which the desired message signal is stored. Alternatively, there may be one read-out switch, which the subscriber will have to operate n times at the maximum to have the desired message signal read out. A radio paging receiver having one of such functions, which indicates the receipt of and stores every message signal received, is very convenient because it allows a long enough time for its bearer to take a plurality of actions.
However, the number of memory circuits is limited by elements of software and, accordingly, if more message signals than the memory circuits are received, the early signal or signals will have to be erased in the order of arrival. Thus, even if one of the plurality of memorized signals contains important information and has to be kept for a long period, it may have to be indiscriminately erased upon arrival of an extra message or messages. Normally, most of the message signals received can be promptly responded to and therefore erased soon, and keeping obsolete messages would unnecessarily complicate the subsequent procedures. With the aforementioned setup which requires the read-out switch to be operated as many times as the desired memory circuit calls for, for instance, there would be a corresponding increase in the required number of switching actions, the number of switches would have to be correspondingly greater. Moreover, a greater number of memory circuits means a correspondingly higher cost.